From: Qinglin Pan panqinglin2020@iscas.ac.cn
[ Upstream commit 9f2ac64d6ca60db99132e08628ac2899f956a0ec ]
Hi Atish,
It seems that the panic is due to the missing memcpy during kasan_init. Could you please check whether this patch is helpful?
When doing kasan_populate, the new allocated base_pud/base_p4d should contain kasan_early_shadow_{pud, p4d}'s content. Add the missing memcpy to avoid page fault when read/write kasan shadow region.
Tested on: - qemu with sv57 and CONFIG_KASAN on. - qemu with sv48 and CONFIG_KASAN on.
Signed-off-by: Qinglin Pan panqinglin2020@iscas.ac.cn Tested-by: Atish Patra atishp@rivosinc.com Fixes: 8fbdccd2b173 ("riscv: mm: Support kasan for sv57") Link: https://lore.kernel.org/r/20221009083050.3814850-1-panqinglin2020@iscas.ac.c... Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/mm/kasan_init.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c index a22e418dbd82..e1226709490f 100644 --- a/arch/riscv/mm/kasan_init.c +++ b/arch/riscv/mm/kasan_init.c @@ -113,6 +113,8 @@ static void __init kasan_populate_pud(pgd_t *pgd, base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd))); } else if (pgd_none(*pgd)) { base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); + memcpy(base_pud, (void *)kasan_early_shadow_pud, + sizeof(pud_t) * PTRS_PER_PUD); } else { base_pud = (pud_t *)pgd_page_vaddr(*pgd); if (base_pud == lm_alias(kasan_early_shadow_pud)) { @@ -173,8 +175,11 @@ static void __init kasan_populate_p4d(pgd_t *pgd, base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd))); } else { base_p4d = (p4d_t *)pgd_page_vaddr(*pgd); - if (base_p4d == lm_alias(kasan_early_shadow_p4d)) + if (base_p4d == lm_alias(kasan_early_shadow_p4d)) { base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE); + memcpy(base_p4d, (void *)kasan_early_shadow_p4d, + sizeof(p4d_t) * PTRS_PER_P4D); + } }
p4dp = base_p4d + p4d_index(vaddr);